New study finds Mounjaro may not lead to specific side effect while being used for weight loss

A new study has found that Mounjaro may not lead to a worrying side effect when it is used for weight loss purposes.

With weight loss medication being incredibly popular at the minute, the side effects that come with them have been discussed vastly, and it's important for users to know what they could potentially be facing before embarking on their weight loss jab journeys.

But firstly, let's get into the basics.

What is Mounjaro?

Mounjaro is a GLP-1 medication, which was designed to be treat those with type 2 diabetes, has become particularly popular among celebrities and the general public as a way of seemingly losing weight quickly and easily.

It works by activating two receptors called GLP-1 and GIP to increase the level of incretins – hormones - in the body, which also sees users have a significant reduction in their appetite, leading to rapid weight loss.

Weight loss medication, such as Mounjaro, has seen a surge in popularity in the past year (George Frey/Bloomberg via Getty Images)

What is the side effect?

Although the drug has been proven to be extremely effective in helping people lose weight, there are very strict conditions you must meet to be eligible for it on the NHS, as it also comes with a lot of unpleasant side effects.

One of the most worrying of those was that the drug could also lead to muscle loss, which has been linked with health problems such as osteoporosis.

Professor Carl Heneghan, director of Oxford University's Centre for Evidence-Based Medicine, added: "Any drug that reduces muscle mass and bone density is a bad idea for people who are frail and those vulnerable to fractures with osteoporosis.

"The evidence is clear – these drugs carry significant risks and the longer a patient stays on them, the greater the risk."

However, a new study conducted by researchers from the University of Glasgow has found that Mounjaro in particular may actually avoid this side effect, and instead could help users become more toned.

Muscle loss has been associated with Mounjaro (Getty Stock)

What have scientists found?

After analysing the body composition of over 200 people, it was found that the muscle loss in Mounjaro users was no worse than the muscle loss of those who lost weight naturally.

It suggested muscle loss from shedding weight will be similar with or without the injections and in fact found that Mounjaro users lost more fat from inside muscles, which may allow them to better function.

The study's lead author Naveed Sattar, a professor of metabolic medicine at Glasgow University's Institute of Cardiovascular and Medical Sciences, told The Times: “For the majority of people using the weight-loss injection tirzepatide [the active ingredient in Mounjaro], they experience an increase in their capacity for activity, meaning they can often walk for longer or be more active than before.

“Having less muscle fat usually means the remaining fat muscle cells are more efficient in generating power, which could explain the boost to people’s exercise abilities.

"These results are hugely encouraging as less muscle fat is also linked to a reduced risk of cardiovascular disease and type 2 diabetes in many studies. However, we don’t yet know how weight-loss injections remove additional muscle fat, and more evidence is needed to understand the mechanisms involved.”

A new study has suggested Mounjaro may not cause muscle loss (Peter Dazeley via Getty Images)

While the results are promising, it is suggested that more work must be done to effectively assess the strength of people taking Mounjaro.

"As the study was not specifically designed to evaluate muscle-related changes, assessments of strength, mobility, and physical performance are not available," researchers added.

They also said other factors may have lead to loss of fat within muscles.

"There were no specific instructions in our study about dietary changes or exercise training beyond the standard of care at each site and region, and we cannot exclude the influence that individual differences in lifestyle management might have had on the results," scientists wrote.

"It has been reported that resistance exercise training or dietary supplements might exert a positive effect on muscle composition, and are recommended when substantial weight reduction is achieved or expected (eg. after bariatric surgery)."

LADbible has contacted Eli Lilly, Mounjaro's manufacturer, for comment.